Science and technology are systems of problem solving Science is a way we learn about any physical object Technology is a way we then use that object to meet a need or solve a problem.

A septic system is a technology for disposing of sewage and treating wastewater. Wastewater – water that has been used and, as a result, it becomes wastewater (dishwater) Sewage - is wastewater containing human wastes Wastewater, whether from the sink, shower, washing machine or toilet must be treated before it is safe to return to the environment.

Many buildings use a septic system to dispose of sewage and treat wastewater. Sewer line – a separate pipe takes the water from the building to the septic tank. Septic Tank – an underground container for sewage and wastewater, which uses bacteria to break down or decompose the wastes into simpler chemicals that are less harmful to the environment. Sludge – consisting of the heavier waste particles, settles at the bottom of the tank.

The sludge must be pumped out regularly along with the scum that floats on the top of the tank. The treated wastewater filters out of the tank into the ground through a distribution system. Distribution system – a perforated pipe inside a trench that holds treated water until it ca safely seep into the ground. Leach field – area around the septic tank that the water flows into. Any remaining wastes gradually breakdown in leach field soil.

Clean wastewater for entire communities. 4 main steps Preliminary treatment consist of screens that catch large particles of food and trash as the wastewater flows through. Primary Treatment – consists of settling tanks. As in septic tanks, gravity pulls particles to the bottom, forming sludge.

Secondary Treatment – the wastewater is filtered through a bed of gravel covered with bacteria, which, as in the septic tank, breakdown the wastes into simpler chemicals. The water is then pumped into pools for air and sunlight to help purify it. If necessary, chlorine is added to make sure any remaining harmful microorganisms are dead.

Water pollution is a major issue in CT. Water pollution – addition of any substance that has a negative effect on water or the living things that depend on water. Three main sources: humans, human wastes, industrial wastes, and chemical runoff. In order to control pollution, governments, industries, and individuals must all work together.

Food poisoning – an illness caused by contaminated food resulting in fever, diarrhea, cramps – and in very rare cases, death. Bacteria can produce a toxin, or a poison, that causes illness. Food Preservation Technology – making sure food is safe to eat. Microbe-killing technologies include dehydration, pickling, irradiation, and temperature control. The key to preventing food poisoning is to control the number of bacteria in food, prevent growth of bacteria, destroy as many existing bacteria as possible, and avoid recontamination.

The four main forces acting on a bridge are tension, compression, shear, and torsion. Tension – the force stretches a material Compression – the force squeezes or shortens the material. Shear – the force tends to make a material slide. Torsion- the force tends to make a material twist.

The bridges own weight is called dead load. Its traffic is called live load. Bridge Materials – A bridge has so many forces acting on it that the materials chosen must be strong – but they must also be light enough for the bridge foundation to support. Three most common types of Bridges are beam, arch, and suspension.

The simplest with a span supported at each end. The load is carried by supports. Most highway bridges.

Use a system of triangles that cross-brace each other for stability. Best bridge to carry heaviest loads.

Load is carried at the ends of the arch. Arch bridge has each part supported by the part that comes before it, like two staircases meeting in the middle. Puts more stress on the two end supports than a beam bridge does, but it is less likely to deform in the middle. Compression is main force at work.

Most of the load is carried by cables anchored to the banks. The cables are strung through towers, suspending a deck for traffic. Compression pushes down on the deck, but the cables transfer the compression to the towers, which send the compression to the ground. Best bridge to cover a long distance.